In recent years, there has been introduced a satellite communication system in which communication between two points, such as communication between a ship and an aircraft on the earth, is performed by using a satellite that operates on an earth orbit in the outer space. Such a satellite communication system is realized by receiving a signal transmitted from a communication apparatus on the earth by a relay incorporated in a satellite and transmitting (relaying) the signal to other communication apparatuses on the earth. In recent years, along with the increase of data capacity in the satellite communication system, multi-beam transmission that performs data transmission by beams different for regions has been studied. When this multi-beam transmission is realized by a through repeater satellite with conventional analog frequency conversion, as a frequency required for data transmission of an uplink (from a ground station to a satellite), frequencies corresponding to the number of beams need to be secured. To effectively utilize limited frequencies, a channelizer technique has been studied. This channelizer technique can significantly reduce a signal bandwidth required for an uplink by demultiplexing a signal received by a satellite to minimum frequency units, then distributing demultiplexed signals to transmission destination beams, and multiplexing the distributed signals. Furthermore, to prevent a deterioration in the line quality of an uplink due to rain and the like, there has been studied a regenerative relay technique of demodulating, decoding, coding, and modulating a signal received by a relay and then transmitting the signal to a ground station. Further, there has been disclosed a technique in which different communication services can be simultaneously relayed by combining the channelizer technique and the regenerative relay technique that are described above. For example, there has been studied a technique in which regenerative relay is not performed for a best effort service such as the Internet, and is performed only for communication services that require securement of reliability (see Patent Literature 1 and Non Patent Literature 1).